1. Field of the Invention
The present invention relates to an evaporated fuel treating module that absorbs and treats evaporated fuel from a fuel tank and the like of a vehicle to prevent the evaporated fuel from being discharged into the atmosphere.
2. Background Art
It has been known that volume of the evaporated fuel from a fuel system such as a fuel tank, a carburetor and the like increases with rising of temperature. In particular, immediately after a vehicle stops, because the temperature in a fuel tank is being risen and an evaporation of fuel becomes active, so that it is necessary to provide an evaporated fuel treating system having a function of temporarily storing the evaporated fuel.
FIG. 1 is a block diagram to show a configuration of the evaporated fuel treating system in the prior art. In FIG. 1, a reference numeral 1 denotes a fuel tank and a reference numeral 2 denotes a connection pipe for connecting an intake manifold 3 of an engine (not shown) to the fuel tank 1 via a purge solenoid valve 4. The connection pipe 2 is a connection pipe for supplying the evaporated fuel generated from the fuel tank 1 to the engine (not shown) and has, at some midpoint thereof, a canister 5 filled with some amount of absorbent (activated carbon or the like) for absorbing the evaporated fuel generated from the fuel tank 1 and the like. To the canister 5 are connected a pressure sensor 6 that measures the pressure of the whole connection pipe 2 and a canister vent solenoid valve 7 that is usually open and, when a leak check of an evaporation system is made, is closed to introduce a negative pressure from the intake manifold 3 and to keep the negative pressure. To the canister vent solenoid valve 7 are connected an air filer 8 for removing dust in the atmosphere supplied to the intake manifold 3 side which is at a negative pressure during operation and a one-way valve 9 that when the canister 5 side is at a positive pressure, is opened to discharge air passing through the canister 5 and stripped of the evaporated fuel and is closed when the canister 5 side is at a negative pressure.
Further, at a midpoint of the connection pipe 2 between the canister 5 and the fuel tank 1, is provided a two-way valve 10, and a branch pipe 11 bypassing the two-way valve 10 is provided with a bypass solenoid valve 12. In a case where the fuel tank 1 side is controlled at a slightly more positive pressure than the canister 5 side to prevent the evaporated fuel from being generated from the fuel tank 1, when the fuel tank 1 side is made at the slightly more positive pressure, the two-way valve 10 is closed to keep the pressure, and when the fuel tank 1 side is made at a negative pressure or a greatly more positive pressure as compared with the canister 5 side, that is, the atmosphere side, the two-way valve 10 is opened to return the pressure in the fuel tank 1 side to the atmosphere side. The bypass solenoid valve 12 is usually closed and, when the leak check described above is made, is opened irrespective of the state of the two-way valve 10. This is because of the following reason: when a leak check of the connection pipe 2 is made, in the case where the two-way valve 10 is closed, the range of the connection pipe 2 subjected to the leak check is limited to the connection pipe 2 between the canister 5 and the intake manifold 3, so that, to avoid this, the bypass solenoid valve 12 is opened to expand the range of the connection pipe 2 subjected to the leak check to the whole range of the connection pipe 2 and the fuel tank 1.
Further, the fuel tank 1 is provided with an inlet pipe 13 for adding the fuel and the opening portion of the inlet pipe 13 is removably mounted with a cup 14. In addition, a leveling valve 15 is provided at one end of the connection pipe 2 and the connection pipe 2 is provided with a liquid separator 16 for preventing the liquid fuel from moving from the fuel tank 1 to the canister 5 side via the connection pipe 2.
Next, an operation will be described.
First, when the engine (not shown) is started, a negative pressure is generated in the intake manifold 3 of the engine (not shown). During the operation of the engine (not shown), the atmosphere introduced through the air filter 8 separates the evaporated fuel absorbed and held by the absorbent (activated carbon or the like) in the canister 5 to clean the absorbent (activated carbon or the like) and supplies the evaporated fuel to the intake manifold 3 side of the engine (not shown).
Next, immediately after the engine (not shown) is stopped, the temperature in the fuel tank 1 remains high and thus the fuel actively evaporates and the evaporated fuel is temporarily absorbed and held by the absorbent (activated carbon or the like) in the canister 5.
Next, when the leak check is made, the engine is in a state of operation and the intake manifold 3 is at a negative pressure, and thus the canister vent solenoid valve 7 arranged on the atmosphere side of the canister 5 is closed and the purge solenoid valve 4 is opened for a predetermined time to introduce the negative pressure from the intake manifold 3 side and to keep the negative pressure. At this time, the bypass solenoid valve 12 is opened to make the connection pipe 2 communicate through the whole portion to reduce the whole communication pipe 2 to the negative pressure. In a case where the negative pressure is kept it is decided that a leak does not occur, but when the pressure increases it is decided that the leak does occur at some point of the whole closed system.
However, in the evaporated fuel treating system in the prior art, all the parts of the canister 5 as a main part, the pressure sensor 6, the canister vent solenoid valve 7, the air filter 8 and the one-way valve 9 are connected to each other with the pipes, so that mounting the respective parts inevitably requires a work of connecting pipes and hence presents a problem of requiring a large amount of manpower.
Further, the evaporated fuel treating system in the prior art presents a problem that there are many pipe connection portions and that the connection portions are easily separated when a vehicle is broken in an accident.
Still further, the evaporated fuel treating system in the prior art presents a problem that the evaporated fuel adheres to the inside of a rubber parts for connecting the respective parts described above to the pipes and passes bit by bit through the portions from the inside to the outside.
Still further, the evaporated fuel treating system in the prior art presents a problem that a metal portion as a magnetic path of the solenoid valve used as a part easily rusts when it is covered with, for example, an snow melting agent such as calcium chloride scattered while the vehicle is running.
The present invention has been made to solve the problems described above. The object of the present invention is to provide an evaporated fuel treating module that simplifies a work of mounting parts, improves reliability, prevents fuel from passing through connection portions and prevents the metal portions of the parts from rusting.
In this respect, such an evaporated fuel treating system is disclosed, in, for example, Laid open Japanese Patent Publication Hei 09-25857 and Japanese Utility Model Publication Hei 05-17413, but both the evaporated fuel treating systems disclosed in the above Publications can not solve the foregoing problems at the same time.
In an evaporated fuel treating module in accordance with the present invention, a canister vent solenoid valve is received in a first box-shaped space arranged adjacent to a canister on the atmosphere side of the canister; an air filter is received in a second box-shaped space arranged adjacent to the first box-shaped space and the canister; the canister is made to communicate with the first box-shaped space by opening portions formed in their respective wall portions and the first box-shaped space is made to communicate with the second box-shaped space by opening portions formed in their respective wall portions; and a one-way valve is fixed to a cover of the first box-shaped space. Since this configuration makes it possible to finish mounting work only by mounting the module described above on a vehicle, it is possible to simplify the work of mounting the respective parts on the vehicle. Further, since this configuration can eliminate the work of connecting pipes, it is possible to fundamentally prevent the problem in the prior art, that is, to fundamentally prevent the evaporated fuel from adhering to the inside of the rubber parts for connecting the respective parts described above to the pipes and from passing little by little through the rubber parts from the inside to the atmosphere side. Still further, since the solenoid valve is received in the first box-shaped space, it is possible to surely prevent the metal parts of the canister vent solenoid valve from rusting.
In the evaporated fuel treating module in accordance with the present invention, the cover of the first box-shaped space and a power supply connector of the canister vent solenoid valve are integrally molded, wherein the canister vent solenoid valve is received in the first box-shaped space in a state a power supply terminal of the canister vent solenoid valve being protruded from the opening portion of the first box-shaped space, and the cover is mounted on the opening portion of the first box-shaped space in a state the power supply connector being connected to the power supply terminal. In this manner, it is possible to perform the work of mounting the cover on the opening portion of the first box-shaped space and the work of connecting the connector to the terminal at the same time and thus to simplify the work.
In the evaporated fuel treating module in accordance with the present invention, a gap between the power supply terminal of the canister vent solenoid valve and the power supply connector integrally molded with the cover is filled with a potting material. This can ensure the tight sealing of the first box-shaped space.
In the evaporated fuel treating module in accordance with the present invention, the power supply connector integrally molded with the cover is separated from the power supply terminal of the canister vent solenoid valve, and there is provided a connector terminal for connecting the power supply connector to the vicinity of the power supply terminal of the canister vent solenoid valve, one end of the connector terminal being electrically connected to the power supply terminal of the canister vent solenoid valve, the gap between them being filled with a potting material. This can prevent the connector terminal from interfering with the potting work and thus can improve the workability of the potting work.
In the evaporated fuel treating module in accordance with the present invention, the cover of the first box-shaped space and the canister vent solenoid valve are integrally molded. By this arrangement when a unit formed by integrally molding these parts is mounted on the first box-shaped space, it is not necessary to individually mount the respective parts such as the canister vent solenoid valve and the like, which can simplify the work.
In the evaporated fuel treating module in accordance with the present invention, the cover of the first box-shaped space communicating with the canister is integrally mounted with a pressure sensor for detecting the internal pressure of the first box-shaped space. This eliminates the need for providing pipes between the first box-shaped space and the pressure sensor and thus can simplify the mounting work.
In the evaporated fuel treating module in accordance with the present invention, the opening portion of the first box-shaped space is covered with the canister vent solenoid valve. This eliminates the need for providing a covering member for closing the opening portion of the first box-shaped space and thus can reduce the number of parts and manufacturing costs.
The evaporated fuel treating module in accordance with the present invention further includes a two-way valve disposed between the fuel tank and the canister and a bypass solenoid valve that ensures a passage between the fuel tank and the canister when the two-way valve is in a closed state, the two-way valve is received in a third box-shaped space arranged adjacent to the canister on the fuel tank side of the canister, the bypass solenoid valve is received in a fourth box-shaped space arranged adjacent to the third box-shaped space and the canister, and the canister is made to communicate with the third box-shaped space by openings formed in their wall portions and the third box-shaped space is made to communicate with the fourth box-shaped space by openings formed in their wall portions. Since this configuration makes it possible to finish mounting work only by mounting the module described above on the vehicle, it is possible to simplify the work of mounting the respective parts on the vehicle. Further, since this configuration eliminates the work of connecting pipes, it is possible to fundamentally prevent the problem in the prior art, that is, to fundamentally prevent the evaporated fuel from adhering to the inside of the rubber connection portions of the respective parts described above and the pipes and from passing little by little through the portions from the inside to the atmosphere side. Still further, since the bypass solenoid valve is received in the fourth box-shaped space, it is possible to surely prevent the metal parts of the bypass solenoid valve from rusting.
In the evaporated fuel treating module in accordance with the present invention, a cover of the fourth box-shaped space and the power supply connector of the bypass solenoid valve are integrally molded, the bypass solenoid valve is received in the fourth box-shaped space in a state the power supply terminal of the bypass solenoid valve being protruded from the opening portion of the fourth box-shaped space, and the cover is mounted on the opening portion of the fourth box-shaped space in a state the power supply connector being connected to the power supply terminal. This makes it possible to perform the work of mounting the cover on the opening portion of the fourth box-shaped space and the work of connecting the power supply connector to the power supply terminal at the time, and thus can simplify the work.
In the evaporated fuel treating module in accordance with the present invention, the third box-shaped space and the fourth box-shaped space are integrated into a space and an opening portion of the integrated space is covered with the two-way valve and the bypass solenoid valve. This eliminates the need for providing a covering member for closing the opening portion of the third box-shaped space and thus can reduce the number of parts and manufacturing costs.
In the evaporated fuel treating module in accordance with the present invention, the two-way valve and the bypass solenoid valve are integrally molded and a diaphragm for opening and closing the two-way valve is opened and closed by a magnetic drive part of the bypass solenoid valve. This can eliminate the work of mounting the respective valves and thus can simplify the mounting work and also save space.